Using HIPPI switches to build high-performance multiple FDDI ring networks

摘要

It is a commonplace observation that computational power at the desktop is increasing at an exponential rate. This continues two decades after the first single chip VLSI microprocessor became commercially available and it is projected to continue for at least another decade. As a direct consequence, several observations can be made about the revolutionary impacts occurring in data networking: (1) Inexpensive computer power has made it economically feasible to distribute immense computational capacity to the desktop. (2) Distribution has created a demand for sophisticated networks to enable resource sharing among work groups. (3) Placing compute capacity at the point of consumption has removed the communication barrier from the `man/machine' interface. Virtually every user of computer systems is presented with increasingly rich visual paradigms. Current graphical user interfaces are designed to take advantage of bit mapped color displays that have spatial resolutions of 1024 pixels $MUL 1280 pixels and 8 to 24 bits per pixel of color resolution. (4) Standards have been defined and systems are being built to extend the visual paradigm over the networks that interconnect information workers. (5) As a result of the exponential increase in computing capacity available for constant dollars, one would expect the demand networking capacity to increase accordingly. However, as a consequence of observation (4), the rate of increase is far greater. One of the narrow effects of the above has been to accelerate the demand for high performance networking solutions to support the burgeoning users of PCs and workstations. Fiber distributed data interface (FDDI) standard based bridges and routers have received rapid acceptance to provide backbone connections among Ethernet segments. It is not uncommon for an organization to have dozens of Ethernets within a single establishment. The cost of FDDI compatible interface boards for workstations and PCs is declining rapidly. This year the industry expects to see commercial availability of FDDI over twisted copper pair media that will further reduce the cost per connection. This should have the effect, over the next couple of years, of replicating the current multiple Ethernet interconnection problem but with multiple FDDI rings each operating at 100 Mbps. This paper is intended to explore one solution being developed to address what the author expects to be a large demand for the local interconnection of multiple FDDI rings. What is more, it is expected that the increasing trend toward `networked' applications will demand constant performance over networks that span the entire establishment if not an enterprise.